Fuel and air control



Nov. 8, 1932. w. w. WILLIAMS FUEL AND AIR CONTROL Filed June 18. 1928 O O 0 0 0 O O O O O O O O O O O O O 0 O 0 O O O O O 0 Q 0 ATTORNEY.

Patented Nov. 8, 1932 UNITED, STATES PATENT OFFICE FUEL AND AIR CONTROL Application filed June 18,

This invention relates to improvements in liquid fuel burning devices for domestic purposes and more particularly to fuel and air controls for the operation thereof.

Certain type of domestic liquid fuel heaters supply the liquid fuel by gravity to a pot or combustion chamber adapted to be inserted within the fire box of the furnace or heater of a house heating system and in which air for combustion is supplied to the combustion chamber from a casing surrounding the side and bottom of the combustion chamber and having an air intake leading therefrom, the

air for combustion entering through aper tures arranged in the walls of the combustion chamber and the amount of air passing therethrough regulated by a damper in the air intake. In burners of this type the flame is either initially ignited by the throwing into the combustion chamber a piece of burning paper or match or by a gas pilot and the combustion occurs as the incoming fuel spreads over the base of the combustion chamber and Vaporizes and mixes with the air coming in through the sides of the combustion chamber, the heighth of the plane in which the vapors burn above the bottom of the combustion chamber varies with the amount of oil and air supplied so that when a small amount of oil is supplied and a small amount of air the flame occurs near the bottom of the chamber and upon increasing the supplies of both oil and air in proper proportions, the vapors burn at or about the top of the combustion chamber.

It is an object of this invention to provide a device of this character and provide an electric thermostatic control to be placed in a room of the dwelling where the temperature is desired to be maintained at a certain degree which control when the temperature falls below the desired degree, will actuate the burner and which will act conversely when the temperature of the room exceeds that of the desired amount to shut down the burner.

In explaining the embodiments of this 1nvention reference is made to the accompanying sheet ofdrawing illustrating the prefcrred forms, it being understood that the 1928. Serial No. 286,314.

invention is not restricted to the particular burner shown nor tothe particular type of float valve oil supply and that minor detail changes may be made in the various controls without departing from the scope of the invention.

In the drawing:

Figure 1 is a view in side elevation illustrating a liquid fuel burning mechanism with parts broken away showing the combustion chamber and enclosing casing and a portion of the draft pipe in section and the electric wiring of the controls in diagram.

Figure 2 is a top plan view of Figure l with parts of the combustion chamber and surrounding casing broken away.

Figure 3 is a central transverse vertical section illustrating the operating mechanism of the motor switch.

As a means of describing the improved controls forming the subject-matter of this invention, a domestic liquid fuel burning mechanism for domestic heating purposes is illustrated with the understanding that the invention is not restricted to the particular. application thereof, as shown. The liquid fuel burner comprisesa cylindrical combustion chamber 1 provided with a closed bottom 2 and open at the top. A cylindrical casing 3 surrounds the sides and bottom of the combustion chamber and is provided with an air intake in the form of a rectangular draft pipe 4 extending from one side thereof adjacent the bottom and opening at the other end into a fan blower housing 5. The cylindrical casing 3 joins the top of the side walls of the combustion chamber 1 which side Walls are provided with a plurality of small openings arranged in tiers parallel to the bottom of the chamber. A fan blower 6 is mounted within the fan housing 5 and is preferably operated by-the motor shaft of a small motor 7 supported thereabove. ated oil valve chamber 8 is preferably mounted upon the draft pipe 4 adjacent the motor 7 which is connected by the pipe 9 to an oil tank or other source of liquid fuel, not shown, through which the liquid fuel is supplied to the float chamber. The underside of the float chamber is connected to a fuel discharge pipe A float oper- 10 which extends centrally of the draft ipe 4 to the center of the lower side of the ottom 2 of the combustion chamber 1 and at which point is provided with a discharge opening into the combustion chamber. The float valve chamber 8 is a commercial article and formsno partiof this invention, it being suflicient for the understanding of the op-- mixed with the vapors thereof as to cause the flame to burn in a plane adjacent the top of the combustion chamber.

The electricity employed to operate the motor 7 is taken from the commercial line and passes through the house switch S by way of wire 13 to the motor and back through wire 14 to the house switch. A transformer 15 is shown mounted upon the motor which is connected in parallel with the commercial circuit 13 and 14. a

Figures 1 to 3 illustrate an embodiment of this invention in which the burner only operates when the high fire is desired. In this type the burner flame may be ignited by a gas pilot 41 which is shown connected by pipe 42 from an independent gas supply, not shown. The wire 13 leads from the house switch S to the motor 7 and thence through a mercury tube switch 43 before it returns through wire 14 to the house switch S. The transformer 15 is shown connected across the line to wires 13 and 14 so that the transformer is continually in circuit irrespective of the position of the switch 43. The secondary circuit from the transformer passes through wire 44 to the thermostat T and by wire 45 to the boiler control B and thence by wire 46 to a heating coil 47 within the cylindrical casing 48 and from the heating coil 47 by way of wire 49 to the heating coil 19 on the thermostatic strip 20 and thence b way of wire 50 to the other terminal of t e trans-'- former 15. The heating coil 47 is preferably interposed between mica disks, the lower one resting upon the bottom of the casing 48 and the upper one supporting thereonan expansible and contractable element 51, preferably in the form of a cylindrical metallic casing enclosing a gas or liquid readily responsive to changes in temperature to cause the said casing to expand and contract. The mercury tube switch 43 is mounted in a carrier 52 pivoted at one end in brackets 53 extending upward from the cover of the casing 48 which carrier is provided with a power transmitting adjustable screw 54 passing through the carrier and engaging the upper surface of the expansible and contractable member 51 and so adjusted that when the member 51 is in its cool or contracted position, the mercury tube switch will be so tilted as to break the circuit therethrough and when the member 51 expands, when the heating element 47 is energized, the carrier 52 will be rotated about its pivot to tilt the mercury tube switch to close the motor circuit. In practise, the screw 54 is so adjusted that the passage of the control circuit through the heat coils 19 upon the bi-metallic strip 20 for controlling the operation ofthe fuel valve 12 and through the heating element 47, causing the diaphragm 51 to expand, will cause the bi-metallic strip 20 to deform to open the fuel valve 12 before the diaphragm 51 expands sufficiently to engage the screw 54 to tilt the holder 52 to close the motor cirthe holder 53 to tilt and break the motor circuit after the fuel valve 12 is completely closed, thereby causing the fan to operate a suflicient time after the fuel supply is cut off to cause the consumption of such fuel as may remain in the combustion chamber.

.In the type just illustrated and described the gas pilot may burn continually and the low fire valve remain closed so that when desired to operate the burner as the room thermostat calls for heat, the heating elements 47 and 19, being in series with the room thermostat, will not only operate to close the motor circuit but also open the high fire valve whereupon proper fuel and additional air will be both supplied at the same time.

What I claim is:

A domestic liquid fuel burner having a combustion chamber with a pilot light burning therein, a normally inactive electrically operated fuel feed means leading therefrom, a draft pipe connected with a normally inactive motor driven fan adapted to feed air to the chamber, a motor circuit, a control circuit, a thermostatically operated fuel feed valve in the fuel feeding means including a heating element in the control circuit and an independent adjustable thermostatically operated switch in the motor circuit including an electric heating element in the control circuit, an expansible and contractible member responsive thereto to adjustably operate said motor switch, said heating elements connected in series in the control circuit and adapted upon closing the control circuit to cause fuel to be fed to the combustion chamher and cause air to be fed to the combustion chamber in accordance with the adjustment of the motor switch.

Signed at Bloomington, Illinois, this 18th day of June, 1928.

WALTER w. WILLIAMS; 

